The common factors in the fecal-oral route can be summarized as five Fs: fingers, flies, fields, fluids, and food. Diseases caused by fecal-oral transmission include diarrhea, typhoid, cholera, polio and hepatitis.
Villagers during a CLTS triggering exercise go to the place where meals are prepared to observe how flies are attracted to human feces and carry diseases by landing on the food (village near Lake Malawi, Malawi)
School children during a CLTS triggering event in West Bengal, India looking at a glass of water and fresh human feces where the flies pass from the water to the feces and back. This demonstrates how water can get polluted with pathogens.
The foundations for the "F-diagram" being used today were laid down in a publication by WHO in 1958. This publication explained transmission routes and barriers to the transmission of diseases from the focal point of human feces.
Modifications have been made over the course of history to derive modern-looking F-diagrams. These diagrams are used in many sanitation publications. They are set up in a way that fecal–oral transmission pathways are shown to take place via water, hands, arthropods and soil. To make it easier to remember, words starting with the letter "F" are used for each of these pathways, namely fluids, fingers, flies, food, fields, fomites (objects and household surfaces).
Rather than only concentrating on human feces, animal feces should also be included in the F-diagram.
^Finkelstein RA (1996). Baron S; et al. (eds.). Cholera, Vibrio cholerae O1 and O139, and Other Pathogenic Vibrios in: Baron's Medical Microbiology (4th ed.). Univ of Texas Medical Branch. ISBN978-0-9631172-1-2. (via NCBI Bookshelf).
^Meyer EA (1996). Baron S; et al. (eds.). Other Intestinal Protozoa and Trichomonas Vaginalisin: Baron's Medical Microbiology (4th ed.). Univ of Texas Medical Branch. ISBN978-0-9631172-1-2. (via NCBI Bookshelf).